main page modules namespaces classes files
Gecode/J home

PreOrderNodeVisitor.java

Go to the documentation of this file.

/* -*- indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Marco Kuhlmann <kuhlmann@ps.uni-sb.de>
 *
 *  Copyright:
 *     Marco Kuhlmann, 2005
 *
 *  Last modified:
 *     $Date: 2006-10-26 11:31:58 +0200 (Thu, 26 Oct 2006) $ by $Author: tack $
 *     $Revision: 3796 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  See the file "LICENSE" for information on usage and
 *  redistribution of this file, and for a
 *     DISCLAIMER OF ALL WARRANTIES.
 *
 */

package org.gecode.gist;


public class PreOrderNodeVisitor extends DefaultNodeVisitor {
    
    public PreOrderNodeVisitor(NodeCursorInterface theCursor) {
        super(theCursor);
    }
    
    private void backtrack() {
        while (! cursor.mayMoveSidewards() && cursor.mayMoveUpwards()) {
            cursor.moveUpwards();
        }
        if (! cursor.mayMoveUpwards()) {
            cursor = null;
        } else {
            cursor.moveSidewards();
        }
    }
    
    public boolean next() {
        cursor.processCurrentNode();
        if (cursor.mayMoveDownwards()) {
            cursor.moveDownwards();
        } else if (cursor.mayMoveSidewards()) {
            cursor.moveSidewards();
        } else {
            backtrack();
        }
        return (cursor != null);
    }
        
}